Radiotherapy Treatment Time and Overall Survival in Locally Advanced Non-Small Cell Lung Cancer
Menée aux Etats-Unis à partir des données du registre national des cancers portant sur 14 154 patients atteints d'un cancer du poumon non à petites cellules de stade III traité par chimioradiothérapie entre 2004 et 2013, cette étude évalue l'effet d'une radiothérapie sur la survie globale en fonction de la durée du traitement, puis identifie les facteurs associés au prolongement de la radiothérapie
Purpose : Prolonged radiotherapy treatment time (RTT) is associated with worse survival in several malignancies. This study investigated whether delays during radiotherapy are associated with overall survival (OS) in non-small cell lung cancer (NSCLC). Materials and Methods : The National Cancer Data Base was queried for patients with stage III NSCLC who received definitive concurrent chemotherapy and fractionated radiotherapy to standard doses (59.4-70.0 Gy) and fractionation from 2004-2013. RTT was classified as standard or prolonged for each treatment regimen based on radiotherapy dose and number of fractions. Cox proportional hazards models evaluated the association between the following factors and OS: RTT, radiotherapy fractionation, demographic/pathologic factors, and chemotherapeutic agents. Results : Of 14,154 patients, RTT was prolonged in 6,262 (44.2%). Factors associated with prolonged RTT included female gender (odds ratio [OR] 1.21, p<0.0001), black race (OR 1.20, p=0.001), non-private health insurance (OR 1.30, p<0.0001), and lower income (<$63,000/yr., OR 1.20, p<0.0001). Median OS was significantly worse in patients with prolonged RTT compared with standard RTT (18.6 vs. 22.7 mo., p<0.0001); furthermore, OS worsened with each cumulative interval of delay (standard RTT vs. prolonged 1-2 days, 20.5 mo., p=0.009; prolonged 3-5 days, 17.9 mo., p<0.0001; prolonged 6-9 days, 17.7 mo., p<0.0001; prolonged >9 days, 17.1 mo., p<0.0001). On multivariable analysis, prolonged RTT was independently associated with inferior OS (hazard ratio [HR] 1.21, P<0.0001). Prolonged RTT as a continuous variable was also significantly associated with worse OS (HR 1.001, P=0.0007). Conclusion : Delays during radiotherapy appear to negatively impact survival in locally advanced non-small cell lung cancer. Demographic and socioeconomic barriers influencing prolonged RTT are also detailed as a means to address health disparities in this regard. Cumulative interruptions of radiotherapy should be minimized.